The present invention relates to a coupling device and more particularly to a coupling device which permits play-free connection of a precision potentiometer and a movable machine part.
It is known in the art that a determination of the movement of machines, for example the relative displacement movement of a machine setting member, is needed to control shifting movement of the machine. When translatory shifting movement is to be determined by a path measuring device, constructed as a potentiometer, the machine and the potentiometer must be precisely connected to one another and bought into an almost parallel relationship so that the shifting movement of the machine elements can be translated to the slider of the potentiometer. Due to both required tolerances and the very exact guidance which the path measuring device requires, so that measuring can be carried out properly, problems occur in converting the shifting movement into potentiometer displacement that have not been eliminated heretofore.
When the movable parts of the potentiometer and the machine are rigidly coupled, rapid destruction in the potentiometer region occurs, resulting in a continuously increasing measurment error. Loose coupling, however, results in inaccuracies in the conversion of the translatory shifting movement and, further, does not offer the necessary degree of freedom for proper operation and transmission of translatory movement
Accordingly, one object of the present invention is to provide a coupling device which transmits, in a play-free manner, the translatory movement of a machine part to a precision potentiometer, and which concomitantly permits free motion in other directions, namely: parallel displacement in the X and the Y direction, whereby the Z direction is the direction of the to-be measured play-free movement.
Another object of the present invention is to provide such a device which is substantially easy and inexpensive to install, and which can be installed almost completely by unskilled labor without the occurrance of measuring errors or other problems.